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[PATCH v31 11/11] Add documentations about Incremental View Maintenance
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* [PATCH v31 11/11] Add documentations about Incremental View Maintenance
@ 2019-12-20 01:25  Yugo Nagata <nagata@sraoss.co.jp>
  0 siblings, 0 replies; 604+ messages in thread

From: Yugo Nagata @ 2019-12-20 01:25 UTC (permalink / raw)

---
 doc/src/sgml/catalogs.sgml                    |   9 +
 .../sgml/ref/create_materialized_view.sgml    | 124 ++++-
 .../sgml/ref/refresh_materialized_view.sgml   |   8 +-
 doc/src/sgml/rules.sgml                       | 437 ++++++++++++++++++
 doc/src/sgml/system-views.sgml                |   9 +
 5 files changed, 583 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 096ddab481..d4255f1015 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -2231,6 +2231,15 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>relisivm</structfield> <type>bool</type>
+      </para>
+      <para>
+       True if relation is incrementally maintainable materialized view
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>relrewrite</structfield> <type>oid</type>
diff --git a/doc/src/sgml/ref/create_materialized_view.sgml b/doc/src/sgml/ref/create_materialized_view.sgml
index 0d2fea2b97..8c574062db 100644
--- a/doc/src/sgml/ref/create_materialized_view.sgml
+++ b/doc/src/sgml/ref/create_materialized_view.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_name</replaceable>
+CREATE [ INCREMENTAL ] MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_name</replaceable>
     [ (<replaceable>column_name</replaceable> [, ...] ) ]
     [ USING <replaceable class="parameter">method</replaceable> ]
     [ WITH ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]
@@ -60,6 +60,125 @@ CREATE MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_name</replaceable>
   <title>Parameters</title>
 
   <variablelist>
+   <varlistentry>
+    <term><literal>INCREMENTAL</literal></term>
+    <listitem>
+     <para>
+      If specified, some triggers are automatically created so that the rows
+      of the materialized view are immediately updated when base tables of the
+      materialized view are updated. In general, this allows faster update of
+      the materialized view at a price of slower update of the base tables
+      because the triggers will be invoked. We call this form of materialized
+      view as "Incrementally Maintainable Materialized View" (IMMV).
+     </para>
+     <para>
+      When <acronym>IMMV</acronym> is defined without using <command>WITH NO DATA</command>,
+      a unique index is created on the view automatically if possible.  If the view
+      definition query has a GROUP BY clause, a unique index is created on the columns
+      of GROUP BY expressions.  Also, if the view has DISTINCT clause, a unique index
+      is created on all columns in the target list.  Otherwise, if the view contains all
+      primary key attritubes of its base tables in the target list, a unique index is
+      created on these attritubes.  In other cases, no index is created.
+     </para>
+     <para>
+      There are restrictions of query definitions allowed to use this
+      option. The following are supported in query definitions for IMMV:
+      <itemizedlist>
+
+       <listitem>
+        <para>
+         Inner joins (including self-joins).
+        </para>
+       </listitem>
+
+       <listitem>
+        <para>
+         Some built-in aggregate functions (count, sum, avg, min, max) without a HAVING
+         clause.
+        </para>
+        </listitem>
+      </itemizedlist>
+
+      Unsupported queries with this option include the following:
+
+      <itemizedlist>
+       <listitem>
+        <para>
+         Outer joins.
+        </para>
+       </listitem>
+
+       <listitem>
+        <para>
+         Sub-queries.
+        </para>
+       </listitem>
+
+       <listitem>
+        <para>
+         Aggregate functions other than built-in count, sum, avg, min and max.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         Aggregate functions with a HAVING clause.
+        </para>
+       </listitem>
+       <listitem>
+        <para>
+         DISTINCT ON, WINDOW, VALUES, LIMIT and OFFSET clause.
+        </para>
+       </listitem>
+      </itemizedlist>
+
+      Other restrictions include:
+      <itemizedlist>
+
+       <listitem>
+        <para>
+         IMMVs must be based on simple base tables. It's not supported to
+         create them on top of views or materialized views.
+        </para>
+       </listitem>
+
+       <listitem>
+        <para>
+         It is not supported to include system columns in an IMMV.
+         <programlisting>
+CREATE INCREMENTAL MATERIALIZED VIEW  mv_ivm02 AS SELECT i,j FROM mv_base_a WHERE xmin = '610';
+ERROR:  system column is not supported with IVM
+         </programlisting>
+        </para>
+       </listitem>
+
+       <listitem>
+        <para>
+         Non-immutable functions are not supported.
+         <programlisting>
+CREATE INCREMENTAL MATERIALIZED VIEW  mv_ivm12 AS SELECT i,j FROM mv_base_a WHERE i = random()::int;
+ERROR:  functions in IMMV must be marked IMMUTABLE
+         </programlisting>
+        </para>
+        </listitem>
+
+       <listitem>
+        <para>
+         IMMVs do not support expressions that contains aggregates
+        </para>
+       </listitem>
+
+       <listitem>
+        <para>
+         Logical replication does not support IMMVs.
+        </para>
+       </listitem>
+
+      </itemizedlist>
+
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>IF NOT EXISTS</literal></term>
     <listitem>
@@ -155,7 +274,8 @@ CREATE MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_name</replaceable>
       This clause specifies whether or not the materialized view should be
       populated at creation time.  If not, the materialized view will be
       flagged as unscannable and cannot be queried until <command>REFRESH
-      MATERIALIZED VIEW</command> is used.
+      MATERIALIZED VIEW</command> is used.  Also, if the view is IMMV,
+      triggers for maintaining the view are not created.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/refresh_materialized_view.sgml b/doc/src/sgml/ref/refresh_materialized_view.sgml
index 8ed43ade80..a4d729bdf0 100644
--- a/doc/src/sgml/ref/refresh_materialized_view.sgml
+++ b/doc/src/sgml/ref/refresh_materialized_view.sgml
@@ -36,9 +36,13 @@ REFRESH MATERIALIZED VIEW [ CONCURRENTLY ] <replaceable class="parameter">name</
    privilege on the materialized view.  The old contents are discarded.  If
    <literal>WITH DATA</literal> is specified (or defaults) the backing query
    is executed to provide the new data, and the materialized view is left in a
-   scannable state.  If <literal>WITH NO DATA</literal> is specified no new
+   scannable state.  If the view is an incrementally maintainable materialized
+   view (IMMV) and was unpopulated, triggers for maintaining the view are
+   created. Also, a unique index is created for IMMV if it is possible and the
+   view doesn't have that yet.
+   If <literal>WITH NO DATA</literal> is specified no new
    data is generated and the materialized view is left in an unscannable
-   state.
+   state.  If the view is IMMV, the triggers are dropped.
   </para>
   <para>
    <literal>CONCURRENTLY</literal> and <literal>WITH NO DATA</literal> may not
diff --git a/doc/src/sgml/rules.sgml b/doc/src/sgml/rules.sgml
index 7a928bd7b9..73597ea7a5 100644
--- a/doc/src/sgml/rules.sgml
+++ b/doc/src/sgml/rules.sgml
@@ -1100,6 +1100,443 @@ SELECT word FROM words ORDER BY word &lt;-&gt; 'caterpiler' LIMIT 10;
 
 </sect1>
 
+<sect1 id="rules-ivm">
+<title>Incremental View Maintenance</title>
+
+<indexterm zone="rules-ivm">
+ <primary>incremental view maintenance</primary>
+</indexterm>
+
+<indexterm zone="rules-ivm">
+ <primary>materialized view</primary>
+ <secondary>incremental view maintenance</secondary>
+</indexterm>
+
+<indexterm zone="rules-ivm">
+ <primary>view</primary>
+ <secondary>incremental view maintenance</secondary>
+</indexterm>
+
+<sect2 id="rules-ivm-overview">
+<title>Overview</title>
+
+<para>
+    Incremental View Maintenance (<acronym>IVM</acronym>) is a way to make
+    materialized views up-to-date in which only incremental changes are computed
+    and applied on views rather than recomputing the contents from scratch as
+    <command>REFRESH MATERIALIZED VIEW</command> does.  <acronym>IVM</acronym>
+    can update materialized views more efficiently than recomputation when only
+    small parts of the view are changed.
+</para>
+
+<para>
+    There are two approaches with regard to timing of view maintenance:
+    immediate and deferred.  In immediate maintenance, views are updated in the
+    same transaction that its base table is modified.  In deferred maintenance,
+    views are updated after the transaction is committed, for example, when the
+    view is accessed, as a response to user command like <command>REFRESH
+    MATERIALIZED VIEW</command>, or periodically in background, and so on.
+    <productname>PostgreSQL</productname> currently implements only a kind of
+    immediate maintenance, in which materialized views are updated immediately
+    in AFTER triggers when a base table is modified.
+</para>
+
+<para>
+    To create materialized views supporting <acronym>IVM</acronym>, use the
+    <command>CREATE INCREMENTAL MATERIALIZED VIEW</command>, for example:
+<programlisting>
+CREATE <emphasis>INCREMENTAL</emphasis> MATERIALIZED VIEW mymatview AS SELECT * FROM mytab;
+</programlisting>
+    When a materialized view is created with the <literal>INCREMENTAL</literal>
+    keyword, some triggers are automatically created so that the view's contents are
+    immediately updated when its base tables are modified. We call this form
+    of materialized view an Incrementally Maintainable Materialized View
+    (<acronym>IMMV</acronym>).
+<programlisting>
+postgres=# CREATE INCREMENTAL MATERIALIZED VIEW m AS SELECT * FROM t0;
+NOTICE:  could not create an index on materialized view "m" automatically
+HINT:  Create an index on the materialized view for effcient incremental maintenance.
+SELECT 3
+postgres=# SELECT * FROM m;
+ i
+---
+ 1
+ 2
+ 3
+(3 rows)
+
+postgres=# INSERT INTO t0 VALUES (4);
+INSERT 0 1
+postgres=# SELECT * FROM m; -- automatically updated
+ i
+---
+ 1
+ 2
+ 3
+ 4
+(4 rows)
+</programlisting>
+</para>
+
+<para>
+    Some <acronym>IMMV</acronym>s have hidden columns which are added
+    automatically when a materialized view is created. Their name starts
+    with <literal>__ivm_</literal> and they contain information required
+    for maintaining the <acronym>IMMV</acronym>. Such columns are not visible
+    when the <acronym>IMMV</acronym> is accessed by <literal>SELECT *</literal>
+    but are visible if the column name is explicitly specified in the target
+    list. We can also see the hidden columns in <literal>\d</literal>
+    meta-commands of <command>psql</command> commands.
+</para>
+
+<para>
+    In general, <acronym>IMMV</acronym>s allow faster updates of materialized
+    views at the price of slower updates to their base tables. Updates of
+    <acronym>IMMV</acronym> is slower because triggers will be invoked and the
+    view is updated in triggers per modification statement.
+</para>
+
+<para>
+    For example, suppose a normal materialized view defined as below:
+
+<programlisting>
+test=# CREATE INCREMENTAL MATERIALIZED VIEW mv_ivm AS
+        SELECT a.aid, b.bid, a.abalance, b.bbalance
+        FROM pgbench_accounts a JOIN pgbench_branches b USING(bid);
+SELECT 10000000
+
+</programlisting>
+
+    Updating a tuple in a base table of this materialized view is rapid but the
+   <command>REFRESH MATERIALIZED VIEW</command> command on this view takes a long time:
+
+<programlisting>
+test=# UPDATE pgbench_accounts SET abalance = 1000 WHERE aid = 1;
+UPDATE 1
+Time: 0.990 ms
+
+test=# REFRESH MATERIALIZED VIEW mv_normal ;
+REFRESH MATERIALIZED VIEW
+Time: 33533.952 ms (00:33.534)
+</programlisting>
+</para>
+
+<para>
+    On the other hand, after creating <acronym>IMMV</acronym> with the same view
+    definition as below:
+
+<programlisting>
+test=# CREATE INCREMENTAL MATERIALIZED VIEW mv_ivm AS
+        SELECT a.aid, b.bid, a.abalance, b.bbalance
+        FROM pgbench_accounts a JOIN pgbench_branches b USING(bid);
+test=# UPDATE pgbench_accounts SET abalance = 1000 WHERE aid = 1;
+NOTICE:  created index "mv_ivm_index" on materialized view "mv_ivm"
+</programlisting>
+
+    updating a tuple in a base table takes more than the normal view,
+    but its content is updated automatically and this is faster than the
+    <command>REFRESH MATERIALIZED VIEW</command> command.
+
+<programlisting>
+test=# UPDATE pgbench_accounts SET abalance = 1000 WHERE aid = 1;
+UPDATE 1
+Time: 13.068 ms
+</programlisting>
+
+</para>
+
+<para>
+    Appropriate indexes on <acronym>IMMV</acronym>s are necessary for
+    efficient <acronym>IVM</acronym> because it looks for tuples to be
+    updated in <acronym>IMMV</acronym>.  If there are no indexes, it
+    will take a long time.
+</para>
+
+<para>
+    Therefore, when <acronym>IMMV</acronym> is defined, a unique index is created on the view
+    automatically if possible.  If the view definition query has a GROUP BY clause, a unique
+    index is created on the columns of GROUP BY expressions.  Also, if the view has DISTINCT
+    clause, a unique index is created on all columns in the target list. Otherwise, if the
+    view contains all primary key attritubes of its base tables in the target list, a unique
+    index is created on these attritubes.  In other cases, no index is created.
+</para>
+
+<para>
+    In the previous example, a unique index "mv_ivm_index" is created on aid and bid
+    columns of materialized view "mv_ivm", and this enables the rapid update of the view.
+    Dropping this index make updating the view take a loger time.
+<programlisting>
+test=# DROP INDEX mv_ivm_index;
+DROP INDEX
+Time: 67.081 ms
+
+test=# UPDATE pgbench_accounts SET abalance = 1000 WHERE aid = 1;
+UPDATE 1
+Time: 16386.245 ms (00:16.386)
+</programlisting>
+
+</para>
+
+<para>
+    <acronym>IVM</acronym> is effective when we want to keep a materialized
+    view up-to-date and small fraction of a base table is modified
+    infrequently.  Due to the overhead of immediate maintenance, <acronym>IVM</acronym>
+    is not effective when a base table is modified frequently.  Also, when a
+    large part of a base table is modified or large data is inserted into a
+    base table, <acronym>IVM</acronym> is not effective and the cost of
+    maintenance can be larger than the <command>REFRESH MATERIALIZED VIEW</command>
+    command. In such situation, we can use <command>REFRESH MATERIALIZED VIEW</command>
+    and specify <literal>WITH NO DATA</literal> to disable immediate
+    maintenance before modifying a base table. After a base table modification,
+    execute the <command>REFRESH MATERIALIZED VIEW</command> (with <literal>WITH DATA</literal>)
+    command to refresh the view data and enable immediate maintenance.
+</para>
+
+</sect2>
+
+<sect2 id="rules-ivm-support">
+<title>Supported View Definitions and Restrictions</title>
+
+<para>
+    Currently, we can create <acronym>IMMV</acronym>s using inner joins, and some
+    aggregates. However, several restrictions apply to the definition of IMMV.
+</para>
+
+<sect3 id="rules-ivm-support-joins">
+<title>Joins</title>
+<para>
+    Inner joins including self-join are supported. Outer joins are not supported.
+</para>
+</sect3>
+
+<sect3 id="rules-ivm-support-aggregates">
+<title>Aggregates</title>
+<para>
+    Supported aggregate functions are <function>count</function>, <function>sum</function>,
+    <function>avg</function>, <function>min</function>, and <function>max</function>.
+    Currently, only built-in aggregate functions are supported and user defined
+    aggregates cannot be used.  When a base table is modified, the new aggregated
+    values are incrementally calculated using the old aggregated values and values
+    of related hidden columns stored in <acronym>IMMV</acronym>.
+</para>
+
+<para>
+     Note that for <function>min</function> or <function>max</function>, the new values
+     could be re-calculated from base tables with regard to the affected groups when a
+     tuple containing the current minimal or maximal values are deleted from a base table.
+     Therefore, it can takes a long time to update an <acronym>IMMV</acronym> containing
+     these functions.
+</para>
+
+<para>
+    Also note that using <function>sum</function> or <function>avg</function> on
+    <type>real</type> (<type>float4</type>) type or <type>double precision</type>
+    (<type>float8</type>) type in <acronym>IMMV</acronym> is unsafe. This is
+    because aggregated values in <acronym>IMMV</acronym> can become different from
+    results calculated from base tables due to the limited precision of these types.
+    To avoid this problem, use the <type>numeric</type> type instead.
+</para>
+
+    <sect4 id="rules-ivm-restrictions-aggregates">
+    <title>Restrictions on Aggregates</title>
+    <para>
+        There are the following restrictions:
+    <itemizedlist>
+        <listitem>
+        <para>
+            If we have a <literal>GROUP BY</literal> clause, expressions specified in
+           <literal>GROUP BY</literal> must appear in the target list.  This is
+           how tuples to be updated in the <acronym>IMMV</acronym> are identified.
+           These attributes are used as scan keys for searching tuples in the
+           <acronym>IMMV</acronym>, so indexes on them are required for efficient
+           <acronym>IVM</acronym>.
+        </para>
+        </listitem>
+
+        <listitem>
+        <para>
+            <literal>HAVING</literal> clause cannot be used.
+        </para>
+        </listitem>
+    </itemizedlist>
+    </para>
+    </sect4>
+</sect3>
+
+<sect3 id="rules-ivm-general-restricitons">
+<title>Other General Restrictions</title>
+<para>
+    There are other restrictions which generally apply to <acronym>IMMV</acronym>:
+    <itemizedlist>
+        <listitem>
+          <para>
+           Sub-queries cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+           CTEs cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+           Window functions cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            <acronym>IMMV</acronym>s must be based on simple base tables.  It's not
+               supported to create them on top of views, materialized views, foreign tables, inhe.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            LIMIT and OFFSET clauses cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            <acronym>IMMV</acronym>s cannot contain system columns.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            <acronym>IMMV</acronym>s cannot contain non-immutable functions.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            UNION/INTERSECT/EXCEPT clauses cannnot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            DISTINCT ON clauses cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            TABLESAMPLE parameter cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            inheritance parent tables cannnot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            VALUES clause cannnot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            <literal>GROUPING SETS</literal> and <literal>FILTER</literal> clauses cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            FOR UPDATE/SHARE cannot be used.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            targetlist cannot contain columns whose name start with <literal>__ivm_</literal>.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+            targetlist cannot contain expressions which contain an aggregate in it.
+          </para>
+        </listitem>
+
+        <listitem>
+          <para>
+              Logical replication is not supported, that is, even when a base table
+               at a publisher node is modified, <acronym>IMMV</acronym>s at subscriber
+               nodes are not updated.
+          </para>
+        </listitem>
+
+    </itemizedlist>
+</para>
+</sect3>
+
+</sect2>
+
+<sect2 id="rules-ivm-distinct">
+<title><literal>DISTINCT</literal></title>
+
+<para>
+    <productname>PostgreSQL</productname> supports <acronym>IMMV</acronym> with
+    <literal>DISTINCT</literal>.  For example, suppose a <acronym>IMMV</acronym>
+    defined with <literal>DISTINCT</literal> on a base table containing duplicate
+    tuples.  When tuples are deleted from the base table, a tuple in the view is
+    deleted if and only if the multiplicity of the tuple becomes zero.  Moreover,
+    when tuples are inserted into the base table, a tuple is inserted into the
+    view only if the same tuple doesn't already exist in it.
+</para>
+
+<para>
+    Physically, an <acronym>IMMV</acronym> defined with <literal>DISTINCT</literal>
+    contains tuples after eliminating duplicates, and the multiplicity of each tuple
+    is stored in a hidden column named <literal>__ivm_count__</literal>.
+</para>
+</sect2>
+
+<sect2 id="rules-ivm-concurrent-transactions">
+<title>Concurrent Transactions</title>
+<para>
+    Suppose an <acronym>IMMV</acronym> is defined on two base tables and each
+    table was modified in different a concurrent transaction simultaneously.
+    In the transaction which was committed first, <acronym>IMMV</acronym> can
+    be updated considering only the change which happened in this transaction.
+    On the other hand, in order to update the view correctly in the transaction
+    which was committed later, we need to know the changes occurred in
+    both transactions.  For this reason, <literal>ExclusiveLock</literal>
+    is held on an <acronym>IMMV</acronym> immediately after a base table is
+    modified in <literal>READ COMMITTED</literal> mode to make sure that
+    the <acronym>IMMV</acronym> is updated in the latter transaction after
+    the former transaction is committed.  In <literal>REPEATABLE READ</literal>
+    or <literal>SERIALIZABLE</literal> mode, an error is raised immediately
+    if lock acquisition fails because any changes which occurred in
+    other transactions are not be visible in these modes and
+    <acronym>IMMV</acronym> cannot be updated correctly in such situations.
+    However, as an exception if the view has only one base table and
+    <command>INSERT</command> is performed on the table,
+    the lock held on thew view is <literal>RowExclusiveLock</literal>.
+</para>
+</sect2>
+
+<sect2 id="rules-ivm-rls">
+<title>Row Level Security</title>
+<para>
+    If some base tables have row level security policy, rows that are not visible
+    to the materialized view's owner are excluded from the result.  In addition, such
+    rows are excluded as well when views are incrementally maintained.  However, if a
+    new policy is defined or policies are changed after the materialized view was created,
+    the new policy will not be applied to the view contents.  To apply the new policy,
+    you need to refresh materialized views.
+</para>
+</sect2>
+
+</sect1>
+
 <sect1 id="rules-update">
 <title>Rules on <command>INSERT</command>, <command>UPDATE</command>, and <command>DELETE</command></title>
 
diff --git a/doc/src/sgml/system-views.sgml b/doc/src/sgml/system-views.sgml
index 3c8dca8ca3..da22606213 100644
--- a/doc/src/sgml/system-views.sgml
+++ b/doc/src/sgml/system-views.sgml
@@ -1787,6 +1787,15 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>isimmv</structfield> <type>bool</type>
+      </para>
+      <para>
+       True if materialized view is incrementally maintainable
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>definition</structfield> <type>text</type>
-- 
2.25.1


--Multipart=_Fri__29_Mar_2024_23_47_00_+0900_KGpmmDOIs1266Ib1--





^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-06-16 11:54  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-06-16 11:54 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 221 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 160 insertions(+), 110 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index fa98b8b9247..04d39ad8c86 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -93,40 +93,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -173,22 +139,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -197,6 +160,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2613,18 +2579,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2633,7 +2612,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2682,14 +2661,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2705,7 +2684,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2718,7 +2697,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2726,7 +2705,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2735,6 +2714,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2742,16 +2723,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2763,10 +2743,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2794,8 +2774,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2944,10 +2924,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2958,9 +2939,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2968,13 +2949,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -2997,16 +2978,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3077,7 +3058,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3093,41 +3074,65 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
-	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(dest->rri, relation, 0, 0, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3137,12 +3142,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3161,34 +3166,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f9eb23e52c9..b4d5abbaca7 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2660,6 +2660,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v01-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



^ permalink  raw  reply  [nested|flat] 604+ messages in thread

* [PATCH 3/8] Introduce RepackDest structure.
@ 2026-07-15 08:37  Antonin Houska <ah@cybertec.at>
  0 siblings, 0 replies; 604+ messages in thread

From: Antonin Houska @ 2026-07-15 08:37 UTC (permalink / raw)

This is for ChangeContext to handle insertions into two relations: besides the
new relation (whose file will eventually be used by the REPACKed relation), an
"auxiliary relation" is needed sometimes, in order to get the data sorted. The
concept is introduced and explained later in the patch series.
---
 src/backend/commands/repack.c    | 223 ++++++++++++++++---------------
 src/include/commands/repack.h    |  48 +++++++
 src/tools/pgindent/typedefs.list |   1 +
 3 files changed, 161 insertions(+), 111 deletions(-)

diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 19927c15bf3..392332b4b2b 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -95,40 +95,6 @@ typedef struct
 	Oid			indexOid;
 } RelToCluster;
 
-/*
- * The first file exported by the decoding worker must contain a snapshot, the
- * following ones contain the data changes.
- */
-#define WORKER_FILE_SNAPSHOT	0
-
-/*
- * Information needed to apply concurrent data changes.
- */
-typedef struct ChangeContext
-{
-	/* The relation the changes are applied to. */
-	Relation	cc_rel;
-
-	/* Needed to update indexes of cc_rel. */
-	ResultRelInfo *cc_rri;
-	EState	   *cc_estate;
-
-	/*
-	 * Existing tuples to UPDATE and DELETE are located via this index. We
-	 * keep the scankey in partially initialized state to avoid repeated work.
-	 * sk_argument is completed on the fly.
-	 */
-	Relation	cc_ident_index;
-	ScanKey		cc_ident_key;
-	int			cc_ident_key_nentries;
-
-	/* The latest column we need to deform to have the tuple identity */
-	AttrNumber	cc_last_key_attno;
-
-	/* Sequential number of the file containing the changes. */
-	int			cc_file_seq;
-} ChangeContext;
-
 /*
  * Backend-local information to control the decoding worker.
  */
@@ -175,22 +141,19 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd,
 static bool repack_is_permitted_for_relation(RepackCommand cmd,
 											 Oid relid, Oid userid);
 
-static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
-static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									ChangeContext *chgcxt);
-static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-									TupleTableSlot *ondisk_tuple,
-									ChangeContext *chgcxt);
+static void apply_concurrent_changes(ChangeContext *chgcxt);
+static void apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot);
+static void apply_concurrent_update(RepackDest *dest,
+									TupleTableSlot *spilled_tuple,
+									TupleTableSlot *ondisk_tuple);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
 								  TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
-							  TupleTableSlot *locator,
+static bool find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 							  TupleTableSlot *retrieved);
-static bool identity_key_equal(ChangeContext *chgcxt,
-							   TupleTableSlot *locator,
+static bool identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 							   TupleTableSlot *candidate);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
 									   ChangeContext *chgcxt,
@@ -199,6 +162,9 @@ static void initialize_change_context(ChangeContext *chgcxt,
 									  Relation relation,
 									  Oid ident_index_id);
 static void release_change_context(ChangeContext *chgcxt);
+static void initialize_change_dest(RepackDest *dest, Relation relation,
+								   Oid ident_index_id);
+static void release_change_dest(RepackDest *dest);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
 											   TransactionId frozenXid,
@@ -2614,18 +2580,31 @@ RepackCommandAsString(RepackCommand cmd)
 }
 
 /*
- * Apply all the changes stored in 'file'.
+ * Apply all the changes provided by decoding worker.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
+apply_concurrent_changes(ChangeContext *chgcxt)
 {
 	ConcurrentChangeKind kind = '\0';
-	Relation	rel = chgcxt->cc_rel;
+	RepackDest *dest;
+	Relation	rel;
 	TupleTableSlot *spilled_tuple;
 	TupleTableSlot *old_update_tuple;
 	TupleTableSlot *ondisk_tuple;
 	bool		have_old_tuple = false;
 	MemoryContext oldcxt;
+	DecodingWorkerShared *shared;
+	char		fname[MAXPGPATH];
+	BufFile    *file;
+
+	dest = &chgcxt->cc_dest;
+	rel = dest->rel;
+
+	shared = (DecodingWorkerShared *) dsm_segment_address(decoding_worker->seg);
+
+	/* Open the file containing the changes. */
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
+	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
 
 	spilled_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 											 &TTSOpsVirtual);
@@ -2634,7 +2613,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	old_update_tuple = MakeSingleTupleTableSlot(RelationGetDescr(rel),
 												&TTSOpsVirtual);
 
-	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(chgcxt->cc_estate));
+	oldcxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(dest->estate));
 
 	while (true)
 	{
@@ -2683,14 +2662,14 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
+			apply_concurrent_insert(dest, spilled_tuple);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
 			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(dest, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
@@ -2706,7 +2685,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
+			found = find_target_tuple(dest, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "could not find target tuple");
 
@@ -2719,7 +2698,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
+			apply_concurrent_update(dest, spilled_tuple, ondisk_tuple);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -2727,7 +2706,7 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 		else
 			elog(ERROR, "unrecognized kind of change: %d", kind);
 
-		ResetPerTupleExprContext(chgcxt->cc_estate);
+		ResetPerTupleExprContext(dest->estate);
 	}
 
 	/* Cleanup. */
@@ -2736,6 +2715,8 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 	ExecDropSingleTupleTableSlot(old_update_tuple);
 
 	MemoryContextSwitchTo(oldcxt);
+
+	BufFileClose(file);
 }
 
 /*
@@ -2743,16 +2724,15 @@ apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
  * table.
  */
 static void
-apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						ChangeContext *chgcxt)
+apply_concurrent_insert(RepackDest *dest, TupleTableSlot *slot)
 {
 	/* Put the tuple in the table, but make sure it won't be decoded */
-	table_tuple_insert(rel, slot, GetCurrentCommandId(true),
+	table_tuple_insert(dest->rel, slot, GetCurrentCommandId(true),
 					   TABLE_INSERT_NO_LOGICAL, NULL);
 
 	/* Update indexes with this new tuple. */
-	ExecInsertIndexTuples(chgcxt->cc_rri,
-						  chgcxt->cc_estate,
+	ExecInsertIndexTuples(dest->rri,
+						  dest->estate,
 						  0,
 						  slot,
 						  NIL, NULL);
@@ -2764,10 +2744,10 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
  * table.
  */
 static void
-apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
-						TupleTableSlot *ondisk_tuple,
-						ChangeContext *chgcxt)
+apply_concurrent_update(RepackDest *dest, TupleTableSlot *spilled_tuple,
+						TupleTableSlot *ondisk_tuple)
 {
+	Relation	rel = dest->rel;
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
 	TU_UpdateIndexes update_indexes;
@@ -2795,8 +2775,8 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		ExecInsertIndexTuples(chgcxt->cc_rri,
-							  chgcxt->cc_estate,
+		ExecInsertIndexTuples(dest->rri,
+							  dest->estate,
 							  flags,
 							  spilled_tuple,
 							  NIL, NULL);
@@ -2948,10 +2928,11 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
+find_target_tuple(RepackDest *dest, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
+	Relation	rel = dest->rel;
+	Form_pg_index idx = dest->ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval = false;
 
@@ -2962,9 +2943,9 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
+		ScanKey		entry = &dest->ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -2972,13 +2953,13 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
-						   NULL, chgcxt->cc_ident_key_nentries, 0, 0);
-	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
+						   NULL, dest->ident_key_nentries, 0, 0);
+	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
 	while (index_getnext_slot(scan, ForwardScanDirection, retrieved))
 	{
 		/* Be wary of temporal constraints */
-		if (scan->xs_recheck && !identity_key_equal(chgcxt, locator, retrieved))
+		if (scan->xs_recheck && !identity_key_equal(dest, locator, retrieved))
 		{
 			CHECK_FOR_INTERRUPTS();
 			continue;
@@ -3001,16 +2982,16 @@ find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
  * used for temporal constraints.
  */
 static bool
-identity_key_equal(ChangeContext *chgcxt, TupleTableSlot *locator,
+identity_key_equal(RepackDest *dest, TupleTableSlot *locator,
 				   TupleTableSlot *candidate)
 {
-	slot_getsomeattrs(locator, chgcxt->cc_last_key_attno);
-	slot_getsomeattrs(candidate, chgcxt->cc_last_key_attno);
+	slot_getsomeattrs(locator, dest->last_key_attno);
+	slot_getsomeattrs(candidate, dest->last_key_attno);
 
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		ScanKey		entry = &chgcxt->cc_ident_key[i];
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		ScanKey		entry = &dest->ident_key[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
 
@@ -3081,7 +3062,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool do
 	/* Open the file. */
 	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, chgcxt);
+	apply_concurrent_changes(chgcxt);
 
 	BufFileClose(file);
 
@@ -3097,10 +3078,34 @@ static void
 initialize_change_context(ChangeContext *chgcxt,
 						  Relation relation, Oid ident_index_id)
 {
-	chgcxt->cc_rel = relation;
+	initialize_change_dest(&chgcxt->cc_dest, relation, ident_index_id);
+
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
+}
+
+/*
+ * Free up resources taken by a ChangeContext.
+ */
+static void
+release_change_context(ChangeContext *chgcxt)
+{
+	release_change_dest(&chgcxt->cc_dest);
+}
+
+/*
+ * Initialize the RepackDest struct for the given relation, with the given
+ * index as identity index. InvalidOid can be specified to only make the
+ * relation ready for insertions.
+ */
+static void
+initialize_change_dest(RepackDest *dest, Relation relation,
+					   Oid ident_index_id)
+{
+	dest->rel = relation;
+	dest->bistate = GetBulkInsertState();
 
 	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	chgcxt->cc_estate = CreateExecutorState();
+	dest->estate = CreateExecutorState();
 
 	/*
 	 * Set up a range table for the executor, containing our repacked table as
@@ -3149,41 +3154,41 @@ initialize_change_context(ChangeContext *chgcxt,
 		perminfo->updatedCols = updatedCols;
 
 		/* finally we can initialize the range table proper */
-		ExecInitRangeTable(chgcxt->cc_estate, list_make1(rte), perminfos,
+		ExecInitRangeTable(dest->estate, list_make1(rte), perminfos,
 						   bms_make_singleton(1));
 	}
 
 	/* Set up our ResultRelInfo to use for index updates */
-	chgcxt->cc_rri = makeNode(ResultRelInfo);
-	InitResultRelInfo(chgcxt->cc_rri, relation, 1, NULL, 0);
-	ExecOpenIndices(chgcxt->cc_rri, false);
+	dest->rri = makeNode(ResultRelInfo);
+	InitResultRelInfo(dest->rri, relation, 1, NULL, 0);
+	ExecOpenIndices(dest->rri, false);
 
 	/*
 	 * The table's relcache entry already has the relcache entry for the
 	 * identity index; find that.
 	 */
-	chgcxt->cc_ident_index = NULL;
-	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
+	dest->ident_index = NULL;
+	for (int i = 0; i < dest->rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
+		ind_rel = dest->rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
 		{
-			chgcxt->cc_ident_index = ind_rel;
+			dest->ident_index = ind_rel;
 			break;
 		}
 	}
-	if (chgcxt->cc_ident_index == NULL)
+	if (dest->ident_index == NULL)
 		elog(ERROR, "could not find identity index");
 
 	/* Set up for scanning said identity index */
 	{
 		Form_pg_index indexForm;
 
-		indexForm = chgcxt->cc_ident_index->rd_index;
-		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
-		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		indexForm = dest->ident_index->rd_index;
+		dest->ident_key_nentries = indexForm->indnkeyatts;
+		dest->ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
 		for (int i = 0; i < indexForm->indnkeyatts; i++)
 		{
 			ScanKey		entry;
@@ -3193,12 +3198,12 @@ initialize_change_context(ChangeContext *chgcxt,
 						opcode;
 			StrategyNumber eq_strategy;
 
-			entry = &chgcxt->cc_ident_key[i];
+			entry = &dest->ident_key[i];
 
-			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
-			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opfamily = dest->ident_index->rd_opfamily[i];
+			opcintype = dest->ident_index->rd_opcintype[i];
 			eq_strategy = IndexAmTranslateCompareType(COMPARE_EQ,
-													  chgcxt->cc_ident_index->rd_rel->relam,
+													  dest->ident_index->rd_rel->relam,
 													  opfamily, false);
 			if (eq_strategy == InvalidStrategy)
 				elog(ERROR, "could not find equality strategy for index operator family %u for type %u",
@@ -3217,34 +3222,30 @@ initialize_change_context(ChangeContext *chgcxt,
 						i + 1,
 						eq_strategy, opcode,
 						(Datum) 0);
-			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+			entry->sk_collation = dest->ident_index->rd_indcollation[i];
 		}
 	}
 
 	/* Determine the last column we must deform to read the identity */
-	chgcxt->cc_last_key_attno = InvalidAttrNumber;
-	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
+	dest->last_key_attno = InvalidAttrNumber;
+	for (int i = 0; i < dest->ident_key_nentries; i++)
 	{
-		AttrNumber	attno = chgcxt->cc_ident_index->rd_index->indkey.values[i];
+		AttrNumber	attno = dest->ident_index->rd_index->indkey.values[i];
 
 		Assert(attno > 0);
-		chgcxt->cc_last_key_attno = Max(chgcxt->cc_last_key_attno, attno);
+		dest->last_key_attno = Max(dest->last_key_attno, attno);
 	}
-
-	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
-/*
- * Free up resources taken by a ChangeContext.
- */
 static void
-release_change_context(ChangeContext *chgcxt)
+release_change_dest(RepackDest *dest)
 {
-	ExecCloseIndices(chgcxt->cc_rri);
-	FreeExecutorState(chgcxt->cc_estate);
+	FreeBulkInsertState(dest->bistate);
+	ExecCloseIndices(dest->rri);
+	FreeExecutorState(dest->estate);
 	/* XXX are these pfrees necessary? */
-	pfree(chgcxt->cc_rri);
-	pfree(chgcxt->cc_ident_key);
+	pfree(dest->rri);
+	pfree(dest->ident_key);
 }
 
 /*
diff --git a/src/include/commands/repack.h b/src/include/commands/repack.h
index 27105c10591..07f887e99f6 100644
--- a/src/include/commands/repack.h
+++ b/src/include/commands/repack.h
@@ -16,6 +16,7 @@
 #include <signal.h>
 
 #include "access/hio.h"
+#include "access/skey.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
@@ -39,6 +40,53 @@ typedef struct ClusterParams
 
 extern PGDLLIMPORT volatile sig_atomic_t RepackMessagePending;
 
+/*
+ * Table to apply concurrent data changes to.
+ */
+typedef struct RepackDest
+{
+	/* The relation the changes are applied to. */
+	Relation	rel;
+
+	BulkInsertStateData *bistate;
+
+	/* Needed to update indexes of cc_rel. */
+	ResultRelInfo *rri;
+	EState	   *estate;
+
+	/*
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
+	 */
+	Relation	ident_index;
+	ScanKey		ident_key;
+
+	int			ident_key_nentries;
+
+	/* The latest column we need to deform to have the tuple identity */
+	AttrNumber	last_key_attno;
+} RepackDest;
+
+/*
+ * The first file exported by the decoding worker must contain a snapshot, the
+ * following ones contain the data changes.
+ */
+#define WORKER_FILE_SNAPSHOT	0
+
+/*
+ * Information needed to apply concurrent data changes.
+ *
+ * XXX Now that it's in *.h file, rename to RepackChangeContext?
+ */
+typedef struct ChangeContext
+{
+	/* The destination table. */
+	RepackDest	cc_dest;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel);
 
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..25ac7079099 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2664,6 +2664,7 @@ ReorderBufferTupleCidKey
 ReorderBufferUpdateProgressTxnCB
 ReorderTuple
 RepackCommand
+RepackDest
 RepackDecodingState
 RepackStmt
 ReparameterizeForeignPathByChild_function
-- 
2.52.0


--=-=-=
Content-Type: text/plain
Content-Disposition: attachment;
 filename=v02-0004-Use-multiple-snapshots-to-copy-the-data.patch



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2019-12-20 01:25 [PATCH v31 11/11] Add documentations about Incremental View Maintenance Yugo Nagata <nagata@sraoss.co.jp>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-06-16 11:54 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>
2026-07-15 08:37 [PATCH 3/8] Introduce RepackDest structure. Antonin Houska <ah@cybertec.at>

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